In clinical analyzers that do wet assays, it is well known to mount the reaction cuvettes on a rotating platform that carries them from station to station, at least one of those stations being one which causes mixing within the cuvette. Such for example is shown in German OLS 3,839,080, in which cuvettes 301 are apparently vibrated, p. 7, p. 9-10, and p. 19, of the English translation, to cause mixing of the reaction cuvettes, by a mechanism described as providing a "high rate &lt;frequency&gt; and low amplitude", p. 7, for a few seconds, p. 9. It is not clear what those relative terms might mean.
Such a disclosure is inadequate to teach a satisfactory mixing mechanism. The details that are provided are those on p. 19 and FIG. 11, so that it is clear the entire reaction table 302 is vibrated or shaken. Yet, as shown, that table is a fairly massive plate, so that large amounts of energy are required to vibrate the entire plate at some "high" frequency. This large amount of energy is undesired, and isolation of the table is required so that this vibration does not transfer to the rest of the analyzer. Still further, the researcher is left unaware of what high frequencies and low amplitudes are useful. Finally, when adding certain liquids to another liquid, it can be easily shown that merely shaking the cuvette "for a few seconds" is not likely to cause adequate mixing. There is a particular need to provide adequate mixing when adding a diluent to a liquid sample, such as is often done to allow the assay of an out-lier that has a concentration so high as to be otherwise out-of-range.
Other teachings in the art concerning the mixing of liquid within liquid refer to shaking by oscillating the cuvette forward and backward, to cause as it were a "sloshing" of the liquid. Such a system is used in, e.g., the "Amerlite" analyzer. This also is of limited utility, since vigorous sloshing, while causing desired mixing, also causes a loss of liquid from the cuvettes. Gentle sloshing, while effective to retain the liquid in the cuvette, is slow to cause mixing. That is, 60 minutes or more are required to mix by sloshing gently.
Therefore, there has been a problem with prior art wet assay analyzers in that they do not provide rapid mixing of liquid within liquid, without sloshing liquid out of the open cuvettes.